Growing Number of Chemicals Linked to Brain Disorders in Children

A new study finds that toxic chemicals may be triggering the recent increases in neurodevelopmental disabilities among children, including autism, attention-deficit hyperactivity disorder, and dyslexia.

Researchers at Harvard School of Public Health (HSPH) and Icahn School of Medicine at Mount Sinai say a new way to control the use of these substances is urgently needed.

“The greatest concern is the large numbers of children who are affected by toxic damage to brain development in the absence of a formal diagnosis,” said Philippe Grandjean, adjunct professor of environmental health at HSPH. “They suffer reduced attention span, delayed development, and poor school performance. Industrial chemicals are now emerging as likely causes.”

The new report follows up on a similar study conducted by the researchers in 2006 that identified five industrial chemicals as “developmental neurotoxicants,” or chemicals that can cause brain deficits.

The new study offers updated findings about those chemicals and adds information on six newly recognized ones, including manganese; fluoride; chlorpyrifos and DDT (pesticides); tetrachloroethylene (a solvent); and polybrominated diphenyl ethers (flame retardants).

The study outlines possible links between these newly recognized neurotoxicants and negative health effects on children.

For instance, manganese is associated with diminished intellectual function and impaired motor skills. Solvents are linked to hyperactivity and aggressive behavior, while certain types of pesticides may cause cognitive delays.

Grandjean and co-author Philip Landrigan, Dean for Global Health at Mount Sinai, postulate that many other chemicals contribute to a “silent pandemic” of neurobehavioral deficits that erodes intelligence and disrupts behaviors.

But controlling this pandemic is difficult because of a lack of data to guide prevention and the huge amount of proof needed for government regulation, according to the researchers.

“Very few chemicals have been regulated as a result of developmental neurotoxicity,” they write in the study, which was published in Lancet Neurology.

The researchers say it’s crucial to control the use of these chemicals to protect children’s brain development worldwide. They propose mandatory testing of industrial chemicals and the formation of a new international clearinghouse to evaluate industrial chemicals for potential developmental neurotoxicity.

“The problem is international in scope, and the solution must therefore also be international,” said Grandjean. “We have the methods in place to test industrial chemicals for harmful effects on children’s brain development — now is the time to make that testing mandatory.”

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About Janice Wood

Janice Wood is a long-time writer and editor who began working at a daily newspaper before graduating from college. She has worked at a variety of newspapers, magazines and websites, covering everything from aviation to finance to healthcare.